Take honour killings, for example: an ancient Middle Eastern "custom" in which the statistically worst offenders aren't even Muslims but the Yazidi.

It's funny you mention that. Back when we and our BFFs, the Kurds, were trying to prevent Daesh from slaughtering/starving all the Yazidis, I also had to shake my head a fair bit at the press treatment -- which, of course, everybody (at least in the states) believed -- of the Yazidis as these peaceful, snuggly little oddball Pagans. The honor killings were the first thing that always came to mind, given their propensity for getting into the news for them.

Then again, I wonder to what extent Daesh's decision to use Yazidi girls as sex slaves was designed as a violation of Yazidi "honour". Here is a heartbreaking story about the fate of two of these sex slaves, as told by a defector:

The next day Abu Ali was transferred to another guesthouse in the city of Falluja, not far away, which was under Isis control. This one was crowded with men. Not long after, he was amazed to hear the sound of two girls giggling in the next room. Another fighter told him the girls were Yazidis who had been captured in northern Iraq eight months earlier, when Isis overran the area and sold hundreds of Yazidi women and girls into sex slavery. They were 13 and 14 years old, the man said. They had been offered to the governor of Falluja, who didn't want them, so they were being kept there for the moment. Abu Ali had heard about the Yazidi sex slaves, though he had never encountered any himself. The men called them "sabaya". They were mostly rewards for officers or men who had done well on the front - not for delinquents like Abu Ali. Over the next few hours he heard the girls laughing, and once he heard them sobbing. He assumed it was because they missed their families. Later that day, a shouting match erupted in the dozen or so men in Abu Ali's guesthouse. All of them wanted the sabaya. It went on for half an hour or so, getting increasingly heated.

Then a man in fatigues burst into the guesthouse. He looked like a commander. He asked where the sabaya were, and one of the men pointed to the door of the next room. He marched in without a word. Two loud shots rang out. The man in fatigues walked out again. Abu Ali, sitting in a chair by the door, stared up at him, frozen. "What did you do?" he asked. The man seemed unruffled. "Those girls were causing trouble between the brothers, so I dealt with them," he said. And he walked out.